Collapsible structure for vessel having interior sloping wall

ABSTRACT

A collapsible support structure for assembly inside a vessel having a downwardly and inwardly sloping interior wall includes a base frame including a plurality of pivotably-connected beams and a plurality of base foot modules mounted thereto. The base frame is movable between an expanded configuration for bracing the base foot modules against the vessel, and a collapsed configuration in which the base frame has a width smaller than that of the expanded configuration. The base frame is moved between the expanded and collapsed configurations by pivoting the plurality of beams.

FIELD

The present invention relates to temporary structures, in particular, structures for supporting access platforms, such as scaffolds, inside closed vessels.

I. BACKGROUND

Industrial facilities may include vessels of various types, which may be used for chemical processes, storage, or other purposes. Many such vessels are closed. For example, petroleum refineries typically have numerous closed process vessels and power plants have closed boilers.

Periodically, maintenance needs to be performed on the interiors of such vessels. Processes or stored materials may deposit residues on vessel walls, which may periodically need to be removed from interior walls. In addition, interior equipment may need to be periodically checked or replaced, and repairs may need to be made. Such maintenance often requires the construction of temporary structures within a closed vessel, to support workers and their equipment and allow workers to access parts of the vessel interior.

Conventionally, scaffolding is used to create temporary support platforms. Unfortunately, scaffolding can be very labor-intensive to erect, which can increase cost or downtime associated with maintenance. Moreover, some types of vessels are not flat-bottomed, making construction of scaffolding difficult. For example, vessels may have conical or tapered bottoms which converge downwardly.

SUMMARY

In an aspect, there is disclosed a structure inside a vessel having a downwardly and inwardly sloping interior wall, the structure comprising: a base frame comprising a plurality of pivotably-connected beams and a plurality of base foot modules mounted thereto; wherein the base frame is in an expanded configuration with the base foot modules bracing against the vessel, and the base frame is movable to a collapsed configuration by pivoting the plurality of beams, the collapsed configuration having a width smaller than a width of the expanded configuration.

In another aspect, there is disclosed a method of erecting a structure inside a vessel with a downwardly and inwardly sloping interior wall, the method comprising: unfolding a base frame, comprising a plurality of beams pivotably connected to one another in a closed chain and a plurality of base foot modules mounted thereto, from a collapsed configuration to an expanded configuration, the expanded configuration for bracing against the interior wall and the collapsed configuration having a width smaller than a width of the expanded configuration; positioning the base frame in the vessel so that a plurality of base foot modules brace the base frame against the downwardly-converging wall.

In another aspect, there is disclosed a structure for assembly inside a vessel having a downwardly and inwardly sloping interior wall, the structure comprising: a base frame comprising a plurality of beams pivotably connected to one another to form a closed chain and a plurality of base foot modules mounted to thereto, the foot modules having angled surfaces for engaging the interior wall; the base frame movable between collapsed and expanded configurations by pivoting the plurality of beams, wherein in the expanded configuration, the base frame may be positioned in the vessel so that the plurality of base foot modules brace the base frame against the interior wall, and wherein a width of the base frame in the collapsed configuration is less than a width of the base frame in the expanded configuration.

BRIEF DESCRIPTION OF THE DRAWINGS

In the figures, which illustrate by way of example only, embodiments of this invention:

FIG. 1 is a schematic view of a closed vessel having therein a temporary structure with multiple platforms, exemplary of embodiments of the present disclosure;

FIG. 2A is a perspective view of a base frame of the structure of FIG. 1 in a first configuration;

FIG. 2B is an enlarged perspective view of a foot of the base frame of FIG. 2A;

FIG. 2C is a cross-sectional view of the foot of FIG. 2B;

FIG. 2D is a perspective view of the base frame of FIG. 2A in a second configuration;

FIG. 3 is a perspective view of a platform post of the structure of FIG.

FIG. 4 is a top elevation view of the base frame of FIGS. 2A-2D being passed through an access opening in the closed vessel of claim 1;

FIG. 5A is a perspective view of a first sub-assembly of the structure of FIG. 1, during installation;

FIG. 5B is a cross-sectional view of the sub-assembly of FIG. 5A, along line 5B-5B;

FIG. 6A is a perspective view of a second sub-assembly of the structure of FIG. 1;

FIG. 6B is a cross-sectional view of the sub-assembly of FIG. 6A, along line 6B-6B;

FIG. 7 is a perspective view of a third sub-assembly of the structure of FIG. 1;

FIG. 8 is a perspective view of a fourth sub-assembly of the structure of FIG. 1;

FIG. 9 is a perspective view of a fifth sub-assembly of the structure of FIG. 1;

FIG. 10A is a perspective view of a sixth sub-assembly of the structure of FIG. 1;

FIG. 10B is a cross-sectional view of the sub-assembly of FIG. 10A, along line 10B-10B;

FIG. 11 is a perspective view of a seventh sub-assembly of the structure of FIG. 1; and

FIG. 12 is a perspective view of the structure of FIG. 1 in a fully-constructed state;

FIG. 13A is a schematic view of another base frame in an expanded configuration;

FIG. 13B is a schematic view of the base frame of FIG. 13A in a collapsed configuration;

FIG. 14A is a perspective view of another base frame in an expanded configuration;

FIG. 14B is a perspective view of the base frame of FIG. 14A in a collapsed configuration;

FIG. 15 is a perspective view of another base frame; and

FIG. 16 is a perspective view of a structure suspended from above using wires.

DETAILED DESCRIPTION

FIG. 1 depicts a structure 100 erected inside a closed vessel 102. Vessel 102 is depicted partially transparent so that structure 100 is visible.

Vessel 102 may be a large metallic vessel with a generally cylindrical upper section with an upper interior wall 104, and a lower section with a downwardly and inwardly sloping interior wall 106 defining an inverted frustoconical shape with a downwardly-decreasing cross-sectional area.

As used herein, “inward” and “outward” refer to radial directions of a horizontal cross-section of vessel 102. “Downward” and “upward” refer to directions in a vertical cross-section of vessel 102, depicted in FIG. 1 and “downward” corresponds to the direction of gravity.

As depicted, example vessel 102 is a coker unit and forms part of a petroleum refinery. Vessel 102 has an internal stack 103 which receives input materials from other process units. As is well-known to those skilled in the art, during use of a coker unit, residue in the form of solid coke may accumulate on the interior of the unit.

Vessel 102 may alternatively be used for different purposes. For example, vessel 102 may be a boiler or a storage unit. As will be appreciated, different uses of vessel 102 may result in different types of residue being deposited on its walls.

Vessel 102 is sealed during use, but has a small access portal 108 which may be opened when vessel 102 is not in use to allow workers and equipment to pass into and out of the vessel for maintenance purposes. Access portal 108 may have a generally circular area with relatively small in diameter. Access portal 108 may be just large enough to allow passage of a worker. For example, access portal 108 may be as small as 16 inches in diameter. Accordingly, equipment to be used inside vessel 102 should be small enough to pass through access portal 108, or should be capable of disassembly and transfer into vessel 102 in pieces.

As illustrated, example structure 100 includes a base frame, 110, an intermediate frame 112 and an upper frame 114, which respectively support a base platform 116, intermediate platform 118 and upper platform 120. Each of base platform 116, intermediate platform 118 and upper platform 120 is capable of supporting workers and equipment to provide workers with access to the interior wall of vessel 102. The combination of base platform 116, intermediate platform 118 and upper platform 120 allow workers to access substantially all of interior walls 104, 106 of vessel 102.

A plurality of posts 122 extends upwardly from base frame 110 to support intermediate frame 112. An upper set of posts 122′ extends upwardly from posts 122 to support upper frame 114. Upper posts 122′ are identical to posts 122, except that they may have different lengths. Components of posts 122′ are likewise labelled with the same numbers as the corresponding components of posts 122, and a prime (′) symbol.

Structure 100 is supported by interior wall 106 of vessel 102. Specifically, each of base frame 110 and posts 122 braces against interior wall 106 to cooperatively bear the weight of structure 100 and any workers or equipment supported thereon. Base frame 110 has a plurality of base foot modules 150 attached thereto. Base foot modules 150 conform to the slope of lower interior wall 106 of vessel 102 to engage vessel 102 when base frame 100 is subjected to a downward force. Each of posts 122 has at least one post foot module 170 (FIG. 3), which likewise conforms to the slope of and engages lower interior wall 106. Downward loads applied to structure 100, such as the weight of workers and equipment, tend to wedge base frame 110 and posts 122 against downwardly and inwardly sloping lower interior wall 106 of vessel 102.

FIGS. 2A-2D depict base frame 110 in greater detail. Base frame 110 has two support beams 128, 130 which are opposed to one another, and two cross-beams 134, 136 which are opposed to one another. Support beams 128, 130 and cross-beams 134, 136 may be formed of metal (e.g. aluminium or steel) and may be solid or hollow, with wall thickness chosen to provide sufficient strength. The size and wall thickness of support beams 128, 130 and cross-beams 134, 136 may depend on the maximum load that structure 100 is intended to support.

Cross-beams 134, 136 extend between support beams 128, 130. The ends of cross-beams 134, 136 are pivotably connected to support beams 128, 130 proximate the ends of the support beams 128, 130 at pinned joints 138. Support beams 128, 130 and cross-beams 134, 136 thus form a closed chain.

Each support beam 128, 130 includes two brackets 144 attached to the top surface thereof. Brackets 144 may be welded or otherwise fastened to support beams 128, 130. Each bracket 144 has a pair of upstanding walls 146 and is sized to receive a post 122 (FIG. 1) between walls 146. Walls 146 have apertures 147 therein for receiving a pin to secure a post 122.

Each support beam 128, 130 also has two base foot modules 150 welded to the underside thereof, proximate pinned joints 138. Base foot modules 150 extend downwardly and outwardly from the support beams 128, 130.

One base foot module 150 is shown in greater detail in FIG. 2B. Base foot module 150 has a wedge 151 which is welded to the support beam and a block 152 welded to the wedge 151. A leg member 154 is slidably received in block 152 and can be extended downwardly from block 152 or retracted upwardly into block 152. A screw-type jack 160 controls the extension of leg member 154.

Jack 160 is shown in cross-section in FIG. 2C. Jack 160 includes a threaded screw 162, which extends through block 152 and engages with threads 164 in leg member 154. A nut 153 is threaded on screw 162 and prevents screw 162 from backing out of block 152. Jack 160 is operated by a crank 166, which, when turned in an extending direction, causes screw 162 to rotate and causes threads 164 of leg member 154 to advance along the threads of screw 162, forcing leg 154 downwardly. Conversely, when turned in the opposite direction, crank 166 causes screw 162 to rotate in the opposite direction, retracting leg 154 into block 152.

A foot 156 is mounted to the lower end of leg 154. Foot 156 has a pad 158 for contacting the wall of vessel 102 and is pivotable about leg 154 so that pad 158 can be angled to match the slope of interior wall 106. As depicted, pad 158 is a generally flat rectangular plate. However, in other embodiments, pad 158 may be curved. Foot 156 is formed of metal, such as aluminium or steel. A cushioning material such as wood, plastic or rubber may be affixed to pad 158, for example, using nails or other fasteners or adhesives to avoid damaging the wall of vessel 102.

As noted, cross-beams 134, 136 are pivotably connected to support beams 128, 130 at pinned joints 138. Base frame 110 can therefore be moved between an expanded configuration, shown in FIG. 2A, and a collapsed configuration, shown in FIG. 21), by pivoting the support beams 128,130 and cross-beams 134, 136 relative to one another. In the expanded configuration, base frame 110 forms a generally rectangular shape, whereas in the collapsed configuration, base frame 110 forms parallelogram shape. As is apparent from FIG. 2D, base frame 110 is longer and narrower in its collapsed configuration relative to its expanded configuration.

Base frame 110 also has one or more braces 140. One end of each brace 140 is connected to a support beam 128 or 130 at a pinned joint 142, and the other end is connected to a cross-beam 134, 136 at another pinned joint 142. At least one pinned joint 142 of each brace 140 is capable of disassembly by removing the pin. As will be appreciated, disassembling one pinned joint 142 of a brace 140 frees the brace to rotate about the other pinned joint 142.

When braces 140 are fixed, that is, when both pinned joints 142 of each brace are assembled, braces 140 hold base frame 110 in its expanded configuration. Conversely, when one joint 142 of each brace 140 is disassembled, the braces 140 may be folded against cross-beams 134, 136 as shown in FIG. 2D, allowing base frame 110 to be folded into its collapsed configuration.

With reference to FIG. 3, a post 122 is depicted in detail. Post 122 is formed of metal, such as steel or aluminium. Post 122 may be hollow, with wall thickness selected to provide adequate strength to support structure 100. Optionally, post 122 may have internal reinforcements to provide additional strength. As will be appreciated, the size and wall thickness of post 122 depends on the maximum load that structure 100 is intended to support. In some embodiments, post 122 may be sized to match standard scaffolding sizes. For example, post 122 may be formed from 1.9 inch outer diameter scaffold tube with 0.2 inch thick walls. If the diameter of post 122 is a standard scaffolding size, standard accessories such as scaffolding clamps may be used in conjunction with post 122.

Post 122 has holes 168 bored transversely therethrough proximate its lower end. Holes 168 align with holes 147 when a lower end of a post 122 is received in a bracket 144. Thus, a pin can be inserted through holes 168, 147 to form a clevis joint.

An extension sleeve 165 is fitted to the top of post 122. Extension sleeve 165 has a top section 167 and bottom section 169, each of which is welded to a block 172 of a post foot module 170. Each of top section 167 and bottom section 169 is hollow and is sized to fit over the end of post 122. Extension sleeve 165 is fitted to a post 122 by sliding bottom section 169 over the top end of the post 122. As shown, bottom section 169 is pinned to post 122. However, bottom section 169 may alternatively be secured to post 122 using other types of fasteners or by welding.

In some embodiments, bottom section 169 of sleeve 165 may be adjustably connected to post 122 so that sleeve 165 can be extended.

Post foot module 170 includes a block 172 welded to top section 167 and bottom section 169 of sleeve 165. A leg member 174 is received in block 172 and is angled downwardly and outwardly from block 172. Leg member 174 is slidable within block 172 so that it may be extended from or retracted into block 172. Extension and retraction of leg member 174 is controlled by a screw-type jack 173, similar to jack 160. That is, jack 173 has a screw member which engages threads in leg member 174, and a crank to rotate the screw member and thereby force leg 174 to extend or retract. A foot 176 is pivotably mounted to leg member 174. Foot 176 may be substantially identical to foot 156 (FIG. 2B). Alternatively, foot 176 may have a pad of different size or shape than 158, as may be required to conform to the shape of the interior wall of vessel 102.

Top section 169 of sleeve 165 is hollow and is sized to receive the lower end of another post 122. Top section 169 has a set of holes 171 which align with holes 168 in the lower end of the post 122 received therein. A pin may be inserted through holes 171, 168 to secure the post 122 to the sleeve 165.

Post 122 has a platform support bracket 178 welded thereto just below sleeve 165. Platform support bracket 178 and leg 174 extend from opposite sides of post 122 so that when post 122 is positioned with foot 176 against the wall of vessel 102, platform support bracket 178 extends inwardly. Platform support bracket 178 is sized to receive a joist 180 and has mounting holes to receive fasteners to secure the received joist to the support bracket 178.

Posts 122 may be provided in left-hand and right-hand versions, which may be mirror images of one another. That is, kg 174 may extend from one side of a left-hand version and an opposite side of a right-hand version. As will be appreciated, left-hand and right-hand versions may therefore be suitable for use on opposite sides of structure 100. Alternatively, posts 122 may be reversible so that any post 122 may be used in a left-hand or right-hand position.

In other embodiments, platform support bracket may be welded to extension 165 rather than to post 122.

Referring again to FIG. 1, each of intermediate platform 118 and upper platform 120 is partially cut away to show the construction of intermediate frame 112 and upper frame 114 in greater detail.

Each of intermediate frame 112 and upper frame 114 is constructed of joists 180, 184 and braces 182. Joists 180, 184 and braces 182 are beams which may be of standard sizes and may be, for example, wooden or metallic. As depicted, joists 180 are composite “I” beams, while joists 184 and braces 182 are simple beams. However, any of joists 180, 184 and braces 184 may be any type of beam, sized to provide appropriate strength.

Joists 180 are mounted to platform support brackets 178 of posts 122 and secured thereto using appropriate fasteners, such as bolts or screws. Braces 182 extend transversely between joists 180 and are mounted thereto using suitable brackets and fasteners (not shown), which will be well known to skilled persons. Joists 184 are mounted atop brackets 182 and extend transversely between joists 180. Joists 184 are likewise secured to joists 180 using suitable brackets and fasteners (not shown) which will be well known to skilled persons.

Joists 184 that are visible in FIG. 1 span the entire distance between joists 180 and are therefore supported at both ends by joists 180. Intermediate frame 112 or upper frame 114 may also include shorter joists 184 which span a smaller distance (shown in FIG. 11). Accordingly, intermediate frame 112 or upper frame 114 may include diagonal braces 192 which have one end fastened to a joist 180 and another end fastened to a brace 182 at a point intermediate the joists 180. Braces 192 reinforce joists 180 and braces 182 and provide support for joists 184 which do not fully span the distance between joists 180.

Intermediate platform 118 and upper platform 120 are constructed atop joists 184 of intermediate frame 112 and upper frame 114, respectively. Platforms 118, 120 are constructed of deck sections 186, which may be formed from metal (e.g. aluminium), plastic, wood, or other suitable material. Deck sections 186 may be attached to one another, for example, using tongue-and-groove construction. Deck, sections 186 may also be secured to joists 184, for example, using suitable fasteners.

Intermediate platform 118 and upper platform 120 are shaped to match the interior cross-sectional shape of vessel 102 at their locations of installation in vessel 102. Thus, intermediate platform 118 may have a cutaway 190 which fits around internal stack 103 of vessel 102. Upper platform 120 likewise has a cutaway 194 which fits around internal stack 103. Deck sections 186 may therefore be unique, with different shapes.

FIGS. 4-12 depict the assembly of structure 100 inside vessel 102. As noted, the interior of vessel 102 can only be accessed through portal 108: Accordingly, structure 100 must be passed through the portal in pieces and assembled inside the vessel.

As shown in FIG. 4, one joint of each brace 140 disassembled and base frame 110 is folded into its collapsed state. Base frame 110 is then passed through portal 108. Notably, the width w₂ of base frame 110 in its collapsed position is smaller than the width w₁ of base frame 110 in its expanded position. Width w₂ is smaller than the width of portal 108. However, width w₁ is larger than the width of portal 108. Thus, base frame 110 cannot be passed through portal 108 in its expanded position, but can be passed through portal 108 in its collapsed position. Accordingly, folding base frame 110 allows it to be passed into vessel 102 through portal 108 intact, without disassembling it into its constituent parts.

After being passed into vessel 102, base frame 110 is installed by wedging base frame 110 into the downwardly-converging section of vessel 102 with base foot modules 150 braced against wall 160.

To install base frame 110, the base frame 110 is unfolded from its collapsed configuration to its expanded configuration. Braces 140 are unfolded and locked in place by inserting pins in all of joints 142. Locking of braces 140 in turn locks base frame 110 in its expanded state.

Each foot 156 is rotated about its respective leg 154 to so that the orientation of pads 158 match the angle of inclination of interior wall 106. Base frame 110 is rested against interior wall 106 so that it is supported by one or more of base foot modules 150.

As noted, the interior of vessel 102 may have one or more layers of residue 188 deposited on its walls from the process conducted or material stored in the vessel during use. The depicted vessel 102 is a coker unit of a petroleum refinery and may have solid coke deposits on its walls. Accumulation of residue 188 may reduce the effective inner diameter of vessel 102. Moreover, residue 188 may be deposited unevenly, so the surface of the residue 188 is contoured differently in different areas. Conveniently, feet 156 may be rotated independently of one another so that pads 158 are at slightly different orientations and each pad sits stably against residue 188 and interior wall 106.

Base frame 110 is moved towards the bottom of vessel 102 and wedges against lower interior wall 106, at a point where the effective inner diameter of vessel 102, taking into account the thickness of residue 188, is approximately equal to the width of base frame 110.

Base frame 110 may initially settle under its own weight so that one or more of feet 156 contact interior wall 106/residue 188, but base frame 110 is not level. Accordingly, using jacks 160, each leg 154 may be extended or retracted as appropriate so that all of feet 156 contact interior wall 106/residue 188, and so that base frame 110 is horizontally level. A downward force may be applied to base frame 110 so that it is securely seated against vessel 102 and to prevent later settling or movement of the base as structure 100 is constructed.

Conveniently, few components need to be assembled to install base frame 110. Braces 140 need to be pinned in place. However, support beams 128, 130 and cross-beams 134, 136 need only be pivoted to the expanded configuration of base frame 110. Similarly, feet 156 are adjusted by rotating around legs 154 and legs 154 are adjusted by operation of jacks 160.

As shown in FIGS. 6A-6B, once base frame 110 is in place and level, four posts 122 are installed to brackets 144. Specifically, the lower end of a post 122 is positioned in each one of brackets 144, so that holes 168 proximate the post's lower end align with holes 147 in the respective bracket 144. A pin (not shown) is inserted through each aligned set of holes 147, 168 to pivotably fix the post 122 to the bracket 144. Each post 122 is oriented so that its respective platform support bracket 178 faces inwardly, that is, generally toward the center of vessel 102, and its respective post foot module 170 faces outwardly, with each foot 176 facing toward the wall of vessel 102.

Each of posts 122 is rotated about its respective bracket 144 so that each foot 176 rests against vessel 102 (or residue 188 on the vessel). Each foot 176 is rotated about its respective leg 174 so that it is angled to match to the slope of interior wall 106 or the contour of residue 188. Since residue 188 may be slightly uneven, feet 176 may be rotated to slightly different angles.

Legs 174 are adjusted by extending each leg 174 using its respective jack 173 until platform support brackets 178 of all four posts 122 are level with one another in a horizontal plane. Legs 174 may be extended differing amounts to compensate for any unevenness in residue 188.

Once posts 122 are installed and adjusted, base platform 116 may be constructed. Deck sections 186 are sequentially laid atop base frame 110. Deck sections 186 may interlock with one another and may be removably fastened to base frame 110, e.g. using screws, bolts, brackets or the like.

Intermediate frame 112 is then constructed. Two joists 180 may be installed, and are supported by posts 122. The ends of joists 180 may be inserted in platform support brackets 178. Joists 180 are securely fastened to platform support brackets 178 using screws, bolts, pins or the like. Joists 180 may be checked after installation to ensure that joists 180 are level, and jacks 173 may be used to adjust legs 174 as necessary to level joists 180.

Braces 182 are then installed. Braces 182 extend perpendicularly between joists 180, with the ends of braces 182 abutting joists 180. Braces 182 are fastened to joists 180 using appropriate brackets and fasteners (not shown), well known to those skilled in the art.

Joists 184 are then installed. Joists 184 sit atop braces 182. Joists 184 are fastened to joists 180 and braces 182 using appropriate brackets and fasteners (not shown), well known to those skilled in the art.

Intermediate platform 118 is then constructed atop joists 184. Like base platform 116, intermediate platform 118 is constructed of deck sections 186, which are sequentially laid atop joists 184 and which may interlock with one another. Deck sections 186 are secured to joists 184 in a suitable manner, for example, using fasteners such as screws or bolts.

In other embodiments, intermediate platform 118 may have a regular shape such that deck sections 186 may be interchangeable. For example, a square platform could be constructed of a number of identically-shaped deck sections 186.

As depicted in FIGS. 10A-10B, the second set of posts 122′ is then installed atop the first set of posts 122.

Posts 122′ are installed atop posts 122 by inserting the lower end of a post 122′ in the sleeve 165 of each post 122. Holes 168′ of posts 122′ are aligned with holes 171 of posts 122. A pin (not shown) is inserted through holes 171, 168′ to secure each post 122′ to its respective underlying post 122.

Sleeves 165 align posts 122′ with posts 122 so that they extend at the same angle, following the slope of interior wall 106.

Each foot 176′ is rested against vessel 102 or residue 188 so that the foot supports at least part of the weight of the respective post 122′. Each foot 176′ may be rotated about leg member 174′ so that the foot 176′ aligns with the surface of vessel 102 or residue 188. Each leg member 174′ is then extended by turning the respective crank 173′ until the platform support brackets 178′ of all posts 122′ are level, aligned in a horizontal plane with one another.

Adjustment of feet 176′ and legs 174′ securely braces posts 122′ against vessel 102 so that upper frame 114 may be constructed thereon.

Upper frame 114 is constructed in a manner similar to that of intermediate frame 112. Joists 180 are first installed and extend between platform support brackets 178′ on two adjacent posts 122′. Joists 180 are securely fastened to platform support brackets 178′ using screws, bolts, pins or the like.

Braces 182 are then installed and extend perpendicularly between joists 180, with the ends of braces 182 abutting the joists 180. Braces 182 are fastened to joists 180 using brackets and fasteners (not shown) to reinforce and stabilize the joists.

Braces 192 are then installed. One end of each brace 192 is attached to a joist 180 using appropriate brackets and fasteners (not shown). The other end of each brace 192 is attached to a brace 182, again using appropriate brackets and fasteners (not shown).

Joists 184 may then be installed. Some of joists 184 sit atop braces 182 and may be generally longer than braces 182 such that they overhang joists 180 and braces 182. Others of joists 184 may be shorter than braces 182 and thus do not fully span the width of upper frame 114. These short joists 184 are supported at one end by one of joists 180 and at the other end by one of braces 192. As will be apparent, braces 192 and short joists 184 leave a gap in upper frame 114 over cutaway 190 in intermediate platform 116. This gap accommodates stack 103 (FIG. 1). Joists 184 are fixed to joists 180 and braces 182, 192 using appropriate brackets and fasteners (not shown).

Upper platform 120 is then constructed atop joists 184. Like base platform 116 and intermediate platform 118, upper platform 120 is constructed of deck sections 186, which are sequentially laid atop joists 184 and which may interlock with one another. Deck sections 186 are secured to joists 184 in a suitable manner, for example, using fasteners such as screws or bolts.

Like intermediate platform 118, upper platform 120 is shaped to match the interior cross-sectional shape of vessel 102. Thus, upper platform 120 has a cutaway 194 which corresponds to cutaway 190 in intermediate platform 118 and which fits around stack 103 (FIG. 1).

As will be appreciated, structure 100 may be dismantled by disassembling its components in the reverse of the process described above. Specifically, upper frame 114 and upper platform 120 may be dismantled, followed by posts 122′, then intermediate frame 112 and intermediate platform 118, then lower platform 116, and posts 122.

Base frame 110 may then be dismantled and removed from vessel 102. Legs 154 may be retracted using jacks 160 and base frame 110 may be lifted upwardly from its installed position in vessel 102 so that feet 156 are no longer braced against vessel 102. At least one joint 142 of each brace 140 is disassembled and base frame 110 is folded into its collapsed configuration.

As depicted, structure 100 is three-tiered, with base, intermediate and upper platforms. However, in other embodiments, structure 100 may have more or fewer than three tiers. Of course, as base frame 110 and posts 122, 122′ bear much of the weight of structure 100, the components thereof may need to be strengthened in embodiments with additional tiers. For example, posts 122, 122′ and beams of base frame 110 may be formed of metal with greater wall thickness.

Base frame 110 is depicted as having two support beams 128, 130 and two cross beams 134, 136. However, in other embodiments, base frame 110 may include more than four beams. For example, as depicted in FIGS. 13A-13B, a base frame 200 may include six beams 202, pivotably joined to one another in a closed hexagonal chain. Base frame 200 may be movable between an expanded configuration, shown schematically in FIG. 13A and a collapsed configuration, shown schematically in FIG. 13B with smaller width than the expanded configuration.

In other embodiments, the base frame may have different configurations of pivotably-connected beams. For example, FIGS. 14A-14B depict a base frame 1100 with a central support member 1260 comprising two parallel support beams 1280, 1300 which are connected proximate their ends using bolts 1302, 1304. Base frame 1100 also includes cross-members 1340, 1360, comprising beams 1342, 1344 and 1362, 1364, respectively. A carrier 1370 comprising plates 1372, 1374 is welded to support beams 1280, 1300. Each of beams 1342, 1344, 1362, 1364 is pivotably connected to support beams 1280, 1300 by carrier 1370. Beams 1342, 1362 are connected using bolts 1376, 1378, while beams 1344, 1364 are connected using removable pins 1380, 1382.

Base frame 1100 has four base foot modules 1500. One base foot module 1500 is welded between support beams 1280, 1300 proximate each end of support member 1260. One base foot module 1500 is welded between beams 1342, 1344 proximate the end of cross member 1340 and one base foot module 1500 is welded between beams 1362, 1364 proximate the end of cross member 1360. Base foot modules 1500 are substantially similar to base foot modules 150 and therefore are not described in detail.

Base frame 1100 is depicted in its expanded configuration in FIG. 14A. In the expanded configuration, bolt 1376 and pin 1380 cooperate to lock cross-member 1340 in place and bolt 1378 and pin 1382 cooperate to lock cross-member 1360 in place. Base frame 1100 may be folded to a collapsed configuration, shown in FIG. 14B, by removing pins 1380, 1382, which frees cross members 1340, 1360 to pivot about bolts 1376, 1378. The width of base frame 1100 in its collapsed configuration is less than the width of base frame 1100 in its expanded configuration. Base frames 110, 1100 can be folded to their respective collapsed configurations by pivoting in a horizontal plane, that is, with their respective beams pivoting about vertical axes. Specifically, base frame 110 can be folded by pivoting its beams 128, 130, 134, 136 about vertical axes defined by pins 138.

In other embodiments, base frames may be configured to be folded in different directions. For example, FIG. 15 depicts a base frame 2100 configured to be folded by pivoting its beams around a horizontal axis.

Base frame 2100 comprises two opposed support beams 2280, 2300. Cross-members 2340, 2360 extend between. Each of cross-members 2340, 2360 includes two beams which are pivotably connected to one another. Specifically, cross-member 2340 is made up of cross-beams 2342, 2344 which are pivotably connected at a bolted joint 2346. Cross-member 2360 is made up of cross-beams 2362, 2364, which are pivotably connected at a bolted joint 2366.

Cross-members 2340, 2360 are connected with support beams 2280, 2300 by four base foot assemblies 2500. Specifically, each base foot assembly 2500 is welded to the end of one of support beams 2280, 2300 and to the end of one of cross-members 2340, 2360. Base foot assemblies 2500 are similar to base foot assemblies 150, 1500 and therefore are not described in detail.

As depicted in FIG. 15, base frame 2100 is in an expanded configuration. Base frame 2100 may be folded to its collapsed configuration by pivoting cross-beams 2342, 2344 and 2362, 2364 about a horizontal axis defined by bolted joints 2346, 2366 in the direction indicated by arrows A. As will be appreciated, the horizontal width of base frame 2100 in its collapsed configuration is smaller than that in its expanded configuration.

In some embodiments, structure 100 may be suspended from above to bear some or all of the weight of structure 100 and any load thereon. For example, FIG. 16 depicts structure 100 with wires 400 attached to upper frame 114. Wires 400 may, for example, be attached using pins, bolts, or other suitable fasteners, and may be anchored to the interior of vessel 102 or to a structure external to vessel 102.

Though vessel 102 has a conical lower section defined by interior wall 106, structure 100 may instead be constructed in a vessel having another downwardly-converging shape. That is, structure 100 could be constructed in other vessels with downwardly and inwardly sloping walls defining shapes whose cross-sectional sizes decrease downwardly. For example, structure 100 could be constructed in a vessel with an inverted pyramid or triangular prism shape.

It will be understood that the word “a” or “an” is intended to mean “one or more” or “at least one”, and any singular form is intended to include plurals herein.

It will further be understood that the term “comprise”, including any variation thereof, is intended to be open-ended and means “include, but not limited to”, unless otherwise specifically indicated to the contrary.

When a list of items is given herein with an “or” before the last item, any one of the listed items or any suitable combination of two or more of the listed items may be selected and used.

Of course, the above-described embodiments are intended to be illustrative only and in no way limiting. The described embodiments are susceptible to many modifications of form, arrangement of parts, details and order of operation. The invention, therefore, is intended to encompass such modification within its scope, as defined by the claims. 

What is claimed is:
 1. A collapsible support structure inside a vessel having a downwardly and inwardly sloping interior wall, said structure comprising: a base frame comprising a plurality of pivotably-connected beams and a plurality of base foot modules mounted thereto; wherein said base frame is in an expanded configuration with said base foot modules bracing against said vessel, and said base frame is movable to a collapsed configuration by pivoting said plurality of beams, said collapsed configuration having a width smaller than a width of said expanded configuration.
 2. The structure of claim 1, further comprising a first plurality of posts mounted to said base frame so that said posts extend upwardly from said base frame at an angle corresponding to the slope of said interior wall.
 3. The structure of claim 2, wherein said first plurality of posts are pivotably mounted to said base frame and said angle is adjustable by pivoting said posts.
 4. The structure of claim 1, wherein each one of said first plurality of posts comprises a post foot module having an angled surface for engaging said downwardly and interior wall.
 5. The structure of claim 4, wherein each of said base foot modules and each of said post foot modules comprises a foot member, pivotably mounted so that the orientation of each of said angled surfaces is independently adjustable.
 6. The structure of claim 5, wherein said base foot modules comprise jacks, each of said foot members being mounted to a jack so as to be extendable towards said interior wall.
 7. The structure of claim 2, wherein each one of said first plurality of posts comprises a platform support bracket to cooperatively support a first plurality of joists and wherein a platform is constructed atop said first plurality of joists.
 8. The structure of claim 2, further comprising a second plurality of posts, each of said second plurality of posts attached to and extending upwardly from a corresponding one of said first plurality of posts.
 9. The structure of claim 8, wherein each one of said second plurality of posts comprises a platform support bracket to cooperatively support a second plurality of joists and wherein a second platform is constructed atop said second plurality of joists.
 10. The structure of claim 1, wherein said interior wall defines an inverted frustoconical shape.
 11. The structure of claim 1, wherein said vessel is a closed vessel having a portal for accessing the interior of said vessel, and wherein said width of said expanded configuration is greater than a width of said portal and said width of said collapsed configuration is less than said width of said portal.
 12. The structure of claim 1, wherein said base frame is movable to said collapsed configuration by pivoting said plurality of beams in a horizontal plane.
 13. The structure of claim 1, wherein said base frame is movable to said collapsed configuration by pivoting said plurality of beams about a horizontal axis.
 14. The structure of claim 1, wherein said structure is suspended by at least one wire.
 15. A method of erecting a collapsible support structure inside a vessel with a downwardly and inwardly sloping interior wall, said method comprising: unfolding a base frame, comprising a plurality of pivotably-connected beams and a plurality of base foot modules mounted thereto, from a collapsed configuration to an expanded configuration, said expanded configuration for bracing against said interior wall and said collapsed configuration having a width smaller than a width of said expanded configuration; positioning said base frame in said vessel so that a plurality of base foot modules brace said base frame against said downwardly-converging wall.
 16. The method of claim 15, further comprising mounting a first plurality of posts to said base frame so that said first plurality of posts extend upwardly from said base frame at an angle corresponding to the slope of said interior wall.
 17. The method of claim 16, wherein said mounting said first plurality of posts comprises pivotably mounting each one of said first plurality of posts to said base frame and pivoting said posts.
 18. The method of claim 15, wherein each of said base foot modules comprises a pivotably mounted foot member and wherein said positioning said base frame comprises pivoting said foot members to correspond to the slope of said interior wall.
 19. The method of claim 15, wherein each of said foot modules is mounted to a jack, and wherein said method further comprises extending or retracting a foot module using one of said jacks.
 20. The method of claim 16, further comprising constructing a platform atop said first plurality of posts.
 21. The method of claim 15, further comprising mounting a second plurality of posts atop said first plurality of posts, each of said second plurality of posts attached to and extending upwardly from a corresponding one of said first plurality of posts.
 22. The method of claim 21, further comprising constructing a second platform atop said second plurality of posts.
 23. The method of claim 15, wherein said interior wall defines an inverted frustoconical shape.
 24. The method of claim 15, further comprising passing said base frame through a portal in said vessel while in said collapsed configuration.
 25. A collapsible support structure for assembly inside a vessel having a downwardly and inwardly sloping interior wall, said structure comprising: a base frame comprising a plurality of pivotably-connected beams and a plurality of base foot modules mounted to thereto, said foot modules having angled surfaces for engaging said interior wall; said base frame movable between collapsed and expanded configurations by pivoting said plurality of beams, wherein in said expanded configuration, said base frame may be positioned in said vessel so that said plurality of base foot modules brace said base frame against said interior wall, and wherein a width of said base frame in said collapsed configuration is less than a width of said base frame in said expanded configuration.
 26. The structure of claim 25, further comprising a first plurality of posts mountable to said base frame so that said first plurality of posts extend upwardly from said base frame at an angle corresponding to the slope of said interior wall.
 27. The structure of claim 26, wherein said first plurality of posts are pivotably mountable to said base frame so that said angle is adjustable.
 28. The structure of claim 25, wherein each of said first plurality of posts comprises a post foot module having an angled surface for engaging said downwardly and interior wall.
 29. The structure of claim 28, wherein each of said base foot modules and each of said post foot modules comprises a foot member, pivotably mounted so that the orientation of each of said angled surfaces is independently adjustable.
 30. The structure of claim 29, wherein said base foot modules comprise jacks, each of said foot members being mounted to a jack so as to be extendable towards said interior wall.
 31. The structure of claim 26, wherein each of said posts comprises a platform support bracket to cooperatively support a first plurality of joists.
 32. The structure of claim 26, further comprising a second plurality of posts, mountable to corresponding ones of said second plurality of posts to extend upwardly therefrom.
 33. The structure of claim 32, wherein each one of said second plurality of posts comprises a platform support bracket to cooperatively support a second plurality of joists.
 34. The structure of claim 25, wherein said interior wall defines an inverted frustoconical shape.
 35. The structure of claim 34, wherein said vessel is a closed vessel having a portal for accessing the interior of said vessel, and wherein said width of said expanded configuration is greater than a width of said portal and said width of said collapsed configuration is less than said width of said portal. 